Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.8 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

This bug appears to be present in Saucy, using kernel 3.11.0-13 on x86_64 (x79 chipset).

Suspend works well for the most part, but sometimes it goes "stubborn" and wakes immediately after suspend is requested (I can confirm that there are no scripts returning non-zero from pm's sleep.d and such).

When it does work, it works like a charm (mostly, USB sometimes doesn't come back properly, but that's another story).

DiegoRivera, if you have a bug in Ubuntu, the Ubuntu Kernel team, Ubuntu Bug Control team, and Ubuntu Bug Squad would like you to please file a new report by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report would delay your problem being addressed as quickly as possible.

No need exists to comment here at this time. After reading the above documentation in it's entirety, if you have further questions or comments, you are welcome to redirect them to the appropriate mailing list or forum via http://www.ubuntu.com/support/community/mailinglists , or you may contact me directly.

It turned out mainline 3.8.10 was unreliable but 3.8.1 is still reliably good so all I know is something changed between 3.8.1 and 3.8.11.

In better news, I am confident that this is upsteam bug 48951. I also have an nvidia mcp5x controller and the workaround to disable async suspend (echo 0 > /sys/power/pm_async) has fixed this for me on stock Ubuntu kernel 3.8.0-34-generic.

So I'm calling this bug confirmed but the upstream bug is "won't fix" due to an unresponsive sata_nv maintainer. Please do whatever makes sense with this bug. Thank you.

Well, the upstream bug listed this commit as introducing the bug: 966f1212e1ac5fe3ddf04479d21488ddb36a2608

I think there are other commits that make it more or less likely to occur but it's very hard to track down. It's not consistently reproducible and very well might be a race condition since we're talking about an asynchronous process here.

It seems this broke in mainline 3.8 between 3.8.6 and 3.8.7. I am running with 3.8.6 now and have not had a suspend failure yet.

That said, Christopher, I don't think I have any more time to debug this, especially if you are unwilling to work with me on on finding the right strategy. I feel like I am spinning my wheels now. I suppose we can just let this bug expire since the upstream bug is "won't fix" anyway.